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Posted: 7/17/2011 6:31:15 PM EDT
| I have the Vortex Viper PST 1-4 moa mounted on a flat top carbine with a 1/9 twist and 55 grain ammo. What distance should it be zeroed at I was thinking 100 yards or am I wrong. |
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The owner’s manual or instructions that came with it should state the recommended distance to zero it in.
Some prefer to zero at different distance. There are a lot of threads that talk about a '50 yard battle zero' or something like that. I never have much luck with the search function, but hopefully someone has the link. I'll look a bit to see if I can find it. |
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There's no set range on where to zero it.....set it wherever you want for the distances you will shoot. If you are having to ask the question, I'd recommend doing some reading up on trajectories and playing about with a ballistics calculator...I like this one as a nice and simple one: Hornady Ballistics Calc. Do some playing around with the calc to work out what your approx holdovers/holdunders are going to be at intermediate distances and come up with a zero that suits your purpose, then go dial it all in at the range. On that calculator for a 55gr bullet, if you don't know what to put, plug in .243 for the ballistics coefficient, and if you have a 16" barrel use something like 2850 FPS for velocity and a sight height of 2.5" - those figures will get your near enough for most 55gr ammo +/- a small amount.
Rule of thumb, most people without a specific range goal in mind either zero at 50, 100 or 200 yards. POI is very similar at 50 and 200 yards, however, if you were to zero at 50 you should always move out and confirm at the further distance (200) whenever possible - undetectable zeroing error at shorter ranges can really be quite pronounced at longer ranges. A lot of people refer to this zero as a 50/200 - it isn't, its either one or the other, and is just close at the reciprocal distance. Might not matter with big (man size) targets, but if you are interested in accuracy and hitting smaller targets, you're always best advised to zero at the longer range...if you do it that way round you will always be near as dammit at the shorter distance. A 100 yard zero is nice and convenient for many shooters, and is fine for most purposes, but the bullet dropoff is much more pronounced after 200 yards than it is zeroing at either 50 or 200. Me personally, I also have a Viper PST and am zeroed at 200 meters (219 yards). My driving reason for this is that the hardest shot at my local 3 gun match is a tiny plate at exactly that distance. By happy coincidence, it also is a nice flat shooting zero for all purposes I can foresee and is great for an almost flat hold from 40 yards through 250 yards with an easily managed very slight holdover at 300. The great thing with the Viper PST however is that you can also dial multiple zeros, quickly adjustable with the top turret...and even if you don't want to do that, the reticle takes a lot of guesswork out of your holdovers. You've got a great scope...take the time to figure the trajectories and you'll get a lot of satisfaction out of it at all ranges. |
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